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Merge pull request #7060 from RasmusWL/hashlib-new-type-tracker

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Approved by yoff
This commit is contained in:
CodeQL CI
2021-11-08 01:31:40 -08:00
committed by GitHub
parent 77aca0a365 9e2bc41648
commit 618d135b0a
2 changed files with 37 additions and 7 deletions
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35
python/ql/lib/semmle/python/frameworks/Stdlib.qll
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@@ -1534,15 +1534,36 @@ private module StdlibPrivate {
// ---------------------------------------------------------------------------
// hashlib
// ---------------------------------------------------------------------------
/** Gets a back-reference to the hashname argument `arg` that was used in a call to `hashlib.new`. */
private DataFlow::TypeTrackingNode hashlibNewCallNameBacktracker(
DataFlow::TypeBackTracker t, DataFlow::Node arg
) {
t.start() and
hashlibNewCallImpl(_, arg) and
result = arg.getALocalSource()
or
exists(DataFlow::TypeBackTracker t2 |
result = hashlibNewCallNameBacktracker(t2, arg).backtrack(t2, t)
)
}
/** Gets a back-reference to the hashname argument `arg` that was used in a call to `hashlib.new`. */
private DataFlow::LocalSourceNode hashlibNewCallNameBacktracker(DataFlow::Node arg) {
result = hashlibNewCallNameBacktracker(DataFlow::TypeBackTracker::end(), arg)
}
/** Holds when `call` is a call to `hashlib.new` with `nameArg` as the first argument. */
private predicate hashlibNewCallImpl(DataFlow::CallCfgNode call, DataFlow::Node nameArg) {
call = API::moduleImport("hashlib").getMember("new").getACall() and
nameArg in [call.getArg(0), call.getArgByName("name")]
}
/** Gets a call to `hashlib.new` with `algorithmName` as the first argument. */
private DataFlow::CallCfgNode hashlibNewCall(string algorithmName) {
exists(DataFlow::Node nameArg |
result = API::moduleImport("hashlib").getMember("new").getACall() and
nameArg in [result.getArg(0), result.getArgByName("name")] and
exists(StrConst str |
nameArg.getALocalSource() = DataFlow::exprNode(str) and
algorithmName = str.getText()
)
exists(DataFlow::Node origin, DataFlow::Node nameArg |
origin = hashlibNewCallNameBacktracker(nameArg) and
algorithmName = origin.asExpr().(StrConst).getText() and
hashlibNewCallImpl(result, nameArg)
)
}

9
python/ql/test/library-tests/frameworks/stdlib/test_md5.py
View File

@@ -27,3 +27,12 @@ hasher = hashlib.new('md5')
hasher.update(b"secret") # $ CryptographicOperation CryptographicOperationInput=b"secret" CryptographicOperationAlgorithm=MD5
hasher.update(b" message") # $ CryptographicOperation CryptographicOperationInput=b" message" CryptographicOperationAlgorithm=MD5
print(hasher.hexdigest())
def foo(arg):
hasher = hashlib.new(arg)
hasher.update(b"secret") # $ CryptographicOperation CryptographicOperationInput=b"secret" CryptographicOperationAlgorithm=MD5
hasher.update(b" message") # $ CryptographicOperation CryptographicOperationInput=b" message" CryptographicOperationAlgorithm=MD5
print(hasher.hexdigest())
foo("md5")